Defects in steel castings

Tato práce se zabývá problematikou vad, které se vyskytují u ocelových odlitků. Na začátku popisuje použití oceli ve slévárenství a vývoj klasifikace vad odlitků. Dále definuje vadu odlitku a její dělení. V hlavní části práce je pozornost věnována nejčastějším vadám ocelových odlitků. Tato literární rešerše se zaměřuje především na popis jednotlivých vad, na příčiny jejich vzniku a uvádí možná opatření k zamezení jejich vzniku. Jsou zde zmíněny možné způsoby odstraňování vad a jejich opravy.This bachelor’s thesis deals with the problems of defects that occur in steel castings. First, the use of steel in the foundry industry and the development of classification of casting defects are described. Furthermore, it defines the term ‘casting defect’ and its division. The main part of the thesis focuses on the most frequent defects in steel castings. The aim of this literature search is to describe the casting defects and their causes and to present possible precautions against their rise. Possible ways of removing the casting defects are discussed as well as their repairs.

Current application of and efforts towards selection strategies in czechoslovakia based on ram and ewe selection

International audienc

Neuronal cell lipidomics and role of cholesterol in α-synuclein binding and aggregation

α-Synuclein is an intrinsically disordered protein whose fold and multimeric state is strongly affected by its environment. The monomers of α-synuclein are enriched in the presynaptic terminals of dopaminergic neurons and seem to have a role in synaptic vesicles recycling and transmitter release. Specific cellular conditions can promote α-synuclein oligomerization which, in the end, results in neuronal death. Lipids seem to be one of these conditions as they are involved in both the native and pathogenic role of α-synuclein. This thesis aims to explore α-synuclein:lipid interaction and how binding to certain lipids may trigger or suppress oligomerization. Furthermore, it aims to establish and use lipidomic techniques for improving the state of knowledge of the lipid environment that might affect α-synuclein function and dysfunction. In Paper I we investigated how cholesterol, the most abundant lipid in mammals, affect α-synuclein affinity towards the lipid bilayer and its oligomerization properties. For this work we tested and optimized the preparation of SMA lipid nanodiscs containing cholesterol. Then, we used these nanodiscs to investigate lipid-mediated changes in fibrillation. We also determined individual amino acid affinities towards the lipid bilayer within the α-synuclein primary sequence. The results suggest the existence of two binding modes: the N-terminal and NAC binding mode. The N-terminal mode seems to be preferred in the presence of anionic lipids (like PG), and this binding leads to a delay in fibrillation onset. The NAC-binding mode seems to be promoted in the presence of lipid bilayers containing cholesterol and speed up α-synuclein oligomerization significantly. In Paper II, we focused on lipidomics methods. We established and optimized a method for lipid isolation, followed by phospholipid identification and quantification using 31P NMR. These methods were first tested on populations of a prokaryotic organism, L. innocua, which were arrested at the C/D boundary of its cell cycle. We discovered that L. innocua modulates its lipid composition, and both cardiolipin and phosphatidylethanolamine fall significantly between the B period and the C/D boundary. When we investigated how these lipid changes could affect the physical properties models of the cell membrane, we observed that the decrease of PE content seems to be compensated for by an increase of PG. In the absence of other factors, this would result in decreasing stored curvature stress, while maintaining membrane fluidity. In Paper III, we used methods established in Paper II for the lipidomic analysis of the SH-SY5Y cell line, which is a commonly used neuronal cell model for Parkinson’s disease research. We also developed an automated script for analysis of the fatty acid chain distribution of phospholipids by LC-MS/MS. We observed several deviations of lipid content from commonly used lipid models and lipid content of brain matter. The most interesting ones are a high content of PC, low content of SM and PS and absence of longer fatty acid chains, including 22:6 PS

Components of heterosis

<p/

Design of Electric Iron

Predmetom mojej bakalárskej práce je vytvoriť elegantný a nadčasový dizajn elektrickej žehličky pre domáce alebo poloprofesionálne použitie v súlade s technickými, ergonomickými a estetickými požiadavkami. Cieľom je vytvoriť produkt, ktorý bude nevšedný, zaujímavý a jednoduchý na použitie.The subject of my bachelor’s thesis is create elegant and timeless design of electric iron for home or semi-professional use in accordance with the technical, ergonomic and aesthetic requirements. The aim is create the product which would be unusual, interesting and easy to use.

The mathematical model of the operating mechanism for turbochargers

Diplomová práca je zameraná na vytvorenie matematického modelu kinematiky ovládacieho mechanizmu turbodúchadla DAVNT (Double-Axle Variable Nozzle Turbine) pre nastavovanie polohy lopatiek. Práca obsahuje krátky prehľad preplňovania a typov turbodúchadiel. Hlavná časť obsahuje matematický model, ktorý skúma správanie mechanizmu pri uvažovaní opotrebenia medzi jednotlivými členmi. Súčasťou je aj hodnotenie zmeny jednotlivých častí v uzloch mechanizmu spôsobených opotrebením a ich vplyv na mechanizmus vzhľadom k dôležitých parametrov charakterizujúcich mechanizmus. Hodnotenie je doplnené optimalizáciou parametrov. Záverečná časť obsahuje výpočet interných statických síl a hodnotenie umiestnenia aktuátora s ohľadom na zaťaženie mechanizmu.The Diploma Thesis is focused to create the mathematical model of operating kinematic model for turbocharger DAVNT (Double Axle Variable Nozzle Turbine) for setting the position of vanes. The work contains a brief overview of supercharge and types of turbochargers. The main part contains a mathematical model which examines the behavior of the mechanism with considering of wear among the parts. It also includes assessment of changing in various parts of the nodes caused by mechanism wear and their influence on the mechanism due to important parameters which characterizes the mechanism. The evaluation is completed by optimizing the parameters. The final section contains the static calculation of internal forces and assessment of actuator position relative to mechanism load.

Spatio-temporal distribution and habitat preference of necrophagous Calliphoridae based on 160 real cases from Switzerland.

Necrophagous blowflies (Diptera: Calliphoridae) are of great importance particularly during investigations of suspicious deaths. Many studies have analyzed the distribution of blowflies based on pig experiments and baited trapping; however, data from real case scenarios are rarely used. In this article, the distribution of blowflies found during investigations of 160 real cases during 1993-2007 in Switzerland is evaluated based on habitat, altitude, and season. Ten species of blowflies were present in 145 out of the 160 cases. The most common species was Calliphora vicina, which occurs throughout the year and was present in 69 % of all cases. Lucilia sericata, Calliphora vomitoria, and L. caesar were identified among the rest of the flies as species of great forensic importance mainly due to their distributional patterns. After a comparison with a similar dataset from Frankfurt, Germany, some surprising differences were determined and discussed. The biggest discrepancies between our dataset and the German dataset were in the occurrences of L. sericata (30 % vs. 86 %, respectively), Phormia regina (5 % vs. 43 %), and L. ampullacea (1 % vs. 45 %). The life-history strategies and intraspecific behavioral variability of blowflies remain understudied, although they can be essential for an unbiased approach during a death investigation. Further research and comparison of occurrence patterns across the area of distribution of blowflies are therefore needed and recommended

The fertility of prolific breeds (Finnsheep, Romanov Sheep, East Friesian Milksheep) and their crosses with mutton merino

International audienc